Cellular Genomic Sites of Hepatitis B Virus DNA Integration

Infection with the Hepatitis B Virus (HBV) is one of the strongest risk-factors for liver cancer (hepatocellular carcinoma, HCC). One of the reported drivers of HCC is the integration of HBV DNA into the host cell genome, which may induce pro-carcinogenic pathways. These reported pathways include: induction of chromosomal instability; generation of insertional mutagenesis in key cancer-associated genes; transcription of downstream cancer-associated cellular genes; and/or formation of a persistent source of viral protein expression (particularly HBV surface and X proteins). The contribution of each of these specific mechanisms towards carcinogenesis is currently unclear. Here, we review the current knowledge of specific sites of HBV DNA integration into the host genome, which sheds light on these mechanisms. We give an overview of previously-used methods to detect HBV DNA integration and the enrichment of integration events in specific functional and structural cellular genomic sites. Finally, we posit a theoretical model of HBV DNA integration during disease progression and highlight open questions in the field.

The p.Ser267Phe variant of sodium taurocholate cotransporting polypeptide (NTCP) supports HBV infection with a low efficiency

Sodium taurocholate cotransporting polypeptide (NTCP) is a functional receptor for human hepatitis B virus (HBV) and its satellite virus Hepatitis D virus (HDV). Physiologically, NTCP is responsible for the majority of sodium-dependent bile acids uptake by hepatocytes. The p.Ser267Phe (S267F) variant of NTCP is a single nucleotide polymorphism (SNP) previously found to cause substantial loss of ability to support HBV and HDV infection and its taurocholic acid uptake function in vitro. Intriguingly, ten individuals were identified as S267F homozygotes in population studies of chronic hepatitis B (CHB) patients. In this study, we identified new HBV isolates from one homozygous S267F mutation carrier and confirmed new isolates also use wildtype-NTCP as a cellular receptor. Furthermore, we demonstrated S267F variant of NTCP, though inefficient, is still a functional receptor for HBV entry. This study advances our understanding of NTCP-mediated HBV infection.

Serum biomarkers for diagnosis and monitoring viral hepatitis and hepatocellular carcinoma

INTRODUCTION

Chronic liver disease due to viral hepatitis continues to be a major global health concern. Timely diagnosis and treatment will prevent cirrhosis, risk of hepatocellular carcinoma (HCC), and requirement for liver transplantation. Numerous serum biomarkers are available for viral hepatitis that are helpful in diagnosis, measuring severity, progression of disease, evaluating the best therapeutic options, and monitoring antiviral treatment response. Determining the clinical use of available diagnostic tests can be challenging for the health care provider. Areas covered: This review article attempts to summarize the established and emerging serological markers for diagnosis and managing viral hepatitis. The literature search was performed in February 2018 and included MEDLINE and Embase databases for recent relevant literature on biomarkers for viral hepatitis. Expert Commentary: Despite the discovery of several candidate biomarkers, translating these to clinical practice in viral hepatitis and HCC remains challenging. While limited availability of the new biomarkers in prevalent geographic areas and significant cost remain major obstacles, there have been exciting developments in this field. Understanding the detection limits and sensitivity of these markers and translating them into clinical use is important in management of viral hepatitis and complications of liver disease such as cirrhosis and hepatocellular cancer.

Hepatitis B Virus Adaptation to the CD8+ T Cell Response: Consequences for Host and Pathogen

Chronic viral hepatitis infections are a major public health concern, with an estimated 290 million individuals infected with hepatitis B virus (HBV) globally. This virus has been a passenger in human populations for >30,000 years, and remains highly prevalent in some settings. In order for this endemic pathogen to persist, viral adaptation to host immune responses is pre-requisite. Here, we focus on the interplay between HBV infection and the CD8+ T cell response. We present the evidence that CD8+ T cells play an important role in control of chronic HBV infection and that the selective pressure imposed on HBV through evasion of these immune responses can potentially influence viral diversity, chronicity, and the outcome of infection, and highlight where there are gaps in current knowledge. Understanding the nature and mechanisms of HBV evolution and persistence could shed light on differential disease outcomes, including cirrhosis and hepatocellular carcinoma, and help reach the goal of global HBV elimination by guiding the design of new strategies, including vaccines and therapeutics.

Novel ADAM-17 inhibitor ZLDI-8 enhances the in vitro and in vivo chemotherapeutic effects of Sorafenib on hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is one of the greatest life threats for Chinese people, and the prognosis of this malignancy is poor due to the strong chemotherapy resistance in patients. Notch pathway components mediate cell survival and epithelial-mesenchymal transition (EMT), and also participate in the induction of multi-drug resistance (MDR). In the present study, we demonstrated the discovery of a novel inhibitor for Notch activating/cleaving enzyme ADAM-17, named ZLDI-8; it inhibited the cleavage of NOTCH protein, consequently decreased the expression of pro-survival/anti-apoptosis and EMT related proteins. ZLDI-8 treatment enhanced the susceptibility of HCC cells to a small molecular kinase inhibitor Sorafenib, and chemotherapy agents Etoposide and Paclitaxel. ZLDI-8 treatment enhanced the effect of Sorafenib on inhibiting tumor growth in nude HCC-bearing mice model. These results suggest that ZLDI-8 can be a promising therapeutic agent to enhance Sorafenib's anti-tumor effect and to overcome the MDR of HCC patients.

Hepatitis B seroprevalence among 5 to 6 years old children in the Philippines born prior to routine hepatitis B vaccination at birth

To assess the prevalence of hepatitis B in the Philippines, we conducted a cross-sectional study among 5 to 6 year old children born in 2007–2008, when the birth dose started to be implemented in the country. The study was conducted from 25 July to 22 October 2013 in 24 provinces and used a 3-stage cluster design and probability-proportional to size sampling. Blood was obtained and sera were tested for hepatitis B surface antigen (HBsAg). The survey included 2,769 children, of whom 26% received a timely birth dose (within 24 hours of birth) and 89% received 3 doses of the hepatitis B vaccine. Due to problems in the initial testing algorithm, only 2,407 sera were available for HBsAg testing, 20 (weighted%, 0.86%) were HBsAg positive. By immunization card and recall, among HBsAg positive children, 2 (weighted%, 20%) received a timely birth dose while 17 (weighted%, 85%) received 3 doses of the hepatitis B vaccine. The seroprevalence of HBsAg that we detected was lower than expected. However, there were several limitations in the field and in the laboratory that may have affected the representativeness of the results. Follow up studies need to be conducted to validate these results.

Recent advances in understanding liver fibrosis: bridging basic science and individualized treatment concepts

Hepatic fibrosis is characterized by the formation and deposition of excess fibrous connective tissue, leading to progressive architectural tissue remodeling. Irrespective of the underlying noxious trigger, tissue damage induces an inflammatory response involving the local vascular system and the immune system and a systemic mobilization of endocrine and neurological mediators, ultimately leading to the activation of matrix-producing cell populations. Genetic disorders, chronic viral infection, alcohol abuse, autoimmune attacks, metabolic disorders, cholestasis, alterations in bile acid composition or concentration, venous obstruction, and parasite infections are well-established factors that predispose one to hepatic fibrosis. In addition, excess fat and other lipotoxic mediators provoking endoplasmic reticulum stress, alteration of mitochondrial function, oxidative stress, and modifications in the microbiota are associated with non-alcoholic fatty liver disease and, subsequently, the initiation and progression of hepatic fibrosis. Multidisciplinary panels of experts have developed practice guidelines, including recommendations of preferred therapeutic approaches to a specific cause of hepatic disease, stage of fibrosis, or occurring co-morbidities associated with ongoing loss of hepatic function. Here, we summarize the factors leading to liver fibrosis and the current concepts in anti-fibrotic therapies.

Which is the best combination of TACE and Sorafenib for advanced hepatocellular carcinoma treatment? A systematic review and network meta-analysis

The aim of this study was to assess the comparative efficacy and safety of combination therapy with transarterial chemoembolization (TACE) and Sorafenib for patients with advanced hepatocellular carcinoma (HCC) through a systematic review and network meta-analysis and identify the best combination of TACE and Sorafenib. We searched databases for publications prior to May 2018. The prespecified efficacy outcomes were the objective response rate, overall survival rate, and time to progression. adverse effects included dermatologic, gastrointestinal, and general disorders. Subgroup analyses, meta-regression, and a network meta-analysis regarding two types of outcomes by different chemotherapy agents in TACE (5-fluorouracil, Adriamycin, Platinum, mitomycin C, hydroxycamptothecin) were included. The study is registered with PROSPERO (CRD42018098541). For efficacy outcomes, subgroups which included 5-fluorouracil and hydroxycamptothecin ranked higher than other chemotherapy agents, while mitomycin C ranked the lowest. For advanced effects, the use of mitomycin C or 5-fluorouracil as the chemotherapy agent ranked higher, while hydroxycamptothecin ranked the lowest. Therefore, we excluded 5-Fu and Mitomycin C in subsequent studies. Additionally, in the evaluation of primary adverse effects by the network meta-analysis, Platinum ranked the highest while hydroxycamptothecin ranked the lowest. Therefore, we excluded Platinum this time. Furthermore, all types of Adriamycin are not same, and some studies included two types of Adriamycin. The network meta-analysis results showed that the TACE (hydroxycamptothecin + pirarubicin) +Sorafenib arm and TACE (hydroxycamptothecin + epirubicin) +Sorafenib arm had significant efficacy differences. In conclusion, for patients with advanced HCC, combination therapy with HCPT plus THP/EPI in TACE and Sorfenib may be used as a first-line treatment.

Seroprevalence of transfusion-transmissible infections (HBV, HCV, syphilis and HIV) among prospective blood donors in a tertiary health care facility in Calabar, Nigeria; an eleven years evaluation

Background

Provision of constant and safe blood has been a public health challenge in Sub-Saharan Africa with high prevalence of transfusion-transmissible infections (TTIs). This study was aimed at determining the trend and seroprevalence of HBV, HCV, syphilis and HIV across the years within study among prospective blood donors at blood bank in University of Calabar Teaching Hospital (UCTH), Calabar, Nigeria.

Methods

A retrospective analysis of blood donor data from January 2005 to December 2016 was conducted in Blood Bank/Donor Clinic of University of Calabar Teaching Hospital, Calabar, Nigeria. Sera samples were screened for hepatitis B surface antigen (HBsAg), antibodies to hepatitis C virus (HCV), human immunodeficiency virus (HIV) 1 and 2 and Treponema pallidum using commercially available immunochromatic based kits.

Results

Out of the 24,979 screened prospective donors in the 2005–2016 study period, 3739 (14.96%) were infected with at least one infective agent. The overall prevalence of HBV, HCV, syphilis and HIV were 4.1, 3.6, 3.1 and 4.2%, respectively. During the period of study, the percentage of all transfusion-transmissible infections declined significantly with remarkable decline in HIV. The study showed male dominated donor pool (98.7%) with higher prevalence (4.2%) of transfusion-transmissible infections than in female donors (0.0%). Commercial donors constituted majority (62.0%) of the donors and as well had the highest prevalence of transfusion-transmissible infections. Majority (62.9%) of the donors were repeat donors.

Conclusion

HBV, HCV, syphilis and HIV have remained a big threat to safe blood transfusion in Nigeria and Sub-Saharan Africa at large. Strict adherence to selection criteria and algorithm of donor screening are recommended.

Prevalence and Risk Factors for Hepatitis B Virus Infection in Roma and Non-Roma People in Slovakia

Prevalence of Hepatitis B is relatively low in developed European countries. However specific subpopulations may exist within each country with markedly different Hepatitis B burden. Roma minority is very numerous in Slovakia and their lifestyle is completely different to non-Roma population. The aim of this study is to map Hepatitis B prevalence in Roma and compare it to non-Roma population and to explore potential socio-economic and health related risk factors. Cross-sectional epidemiology study was performed in Slovakia that included randomly sampled Roma population and geographically corresponding random sampled non-Roma population. Comprehensive questionnaire about risk factors was administered and blood samples were drawn for Hepatitis B serology and virology tests. Altogether 855 participants were included. Global Hepatitis B surface Antigen (HBsAg) positivity rate was 7.7% (i.e., active Hepatitis B) and anti Hepatitis B core IgG antibody (antiHBcIgG) positivity rate was 34.6%. Roma population had significantly higher prevalence of Hepatitis B, both active chronic infection (12.4%; 95% Confidence Interval (CI) 9.58%–15.97% versus 2.8%; 95% CI 1.56%–4.91%; p < 0.0001) and antiHBcIgG positivity (52.8%; 95% CI 48.17%–57.44% versus 25.9%; 95% CI 12.56%–20.02%; p < 0.0001) Main risk factors for HBsAg positivity were Roma ethnicity, male sex and tattoo. Conclusion: There is a very high prevalence of Hepatitis B in Roma communities in Slovakia, with potential for grave medical consequences.

Hepatitis B Virus Genotype E Infection among Egyptian Health Care Workers

BACKGROUND AND OBJECTIVES

Health Care Workers (HCWs) are at a high risk of needle stick injuries and HBV infection in Egypt; this problem is further aggravated by low Hepatitis B (HB) vaccination coverage. Limited data are available on the prevalence of HBV infection in Egyptian HCWs. In this study, we aimed to assess the HBV infection rate and genotypes among Egyptian HCWs.

METHODS

Five hundred and sixty-four (564) HCWs were included. Of them, 258 (45.74%) were health care providers and 306 (54.25%) were non-health care providers. All HCWs completed both the study questionnaires and provided a blood sample for HBV testing. Indeed, all HCWs were tested for Hepatitis B surface antigen (HBsAg) and antibody to Hepatitis B core antigen (anti-HBc), by enzyme-linked immunosorbent assay. HBVDNA was checked for HCWs who tested positive for HBsAg and/or anti-HBc, by nested Polymerase Chain Reaction (PCR). HBVDNA positive HCWs were further subjected to HBV genotyping.

RESULTS

The mean age of included HCWs was 33.0 ± 9.8 years, of whom 319 (56.56%) were males. The mean duration of health care work was 9.3 ± 6.7 years. The frequency of HBsAg and anti-HBc were 1.4%, and 24.5%, respectively. Old age and prolonged duration of health care work were significantly associated with anti-HBc seropositivity. Among 140 HCWs positive for HBsAg and/or anti-HBc, 14 (10 %) had positive HBVDNA by PCR. HBV/E (n = 7), HBV/D (n = 3) and co-infection with E and D (n = 4) genotypes were detected.

CONCLUSION

Egyptian HCWs have a significantly high rate of HBV exposure. The detection of HBV/E genotype among Egyptian HCWs suggests prevalent transmission of HBV/E among Egyptian populations.

An update on the strategies used for the treatment of chronic hepatitis B in children

Chronic hepatitis B (CHB) in children shows a variety of clinical presentations, which influence its natural course and treatment options. This report provides an overview of the ongoing strategies in pediatric CHB management. Interferon-α represents the first choice of treatment in children showing HBV replication and hepatic inflammation (immune active CHB), while the recommendation is to monitor inactive/immune-tolerant children (normal transaminases and low/absent viral replication). When circumstances preclude the use of Interferon-α and in cases of compensated/decompensated cirrhosis, entecavir for children above 2 years of age or tenofovir for children above 12 years of age are the nucleos(t)ide analogues recommended by the most recent guidelines.

Immune response to second vaccination series of hepatitis B virus among booster dose non-responders

OBJECTIVE

To evaluate the response to second vaccination series among post-booster sero-negative children who had previously received compulsory HBV vaccination.

SUBJECTS AND METHODS

After given a booster dose to 1070 children, 103 of them failed to generate anamnestic response (anti-HBs <10 IU/L). Only 91/103 children received additional two doses of recombinant HBV vaccine (i.e. 2(nd) vaccination series) after 1 and 6 months post-booster. Blood sample was withdrawn aseptically one month later for quantitative assessment of anti-HBs to detect development of protective immune response (≥10 IU/L). Immunological vaccination failure was assigned to children who did not develop protective immune response after 2(nd) vaccination series.

RESULTS

Protective immune response was detected among 84/91 children (92.3%). While 7/91 (7.7%) whose age were ≥10 years did not respond and had post-booster undetectable anti-HBs. About 80% of children with post-booster detectable anti-HBs showed significant protective immune response (anti-HBs ≥100 IU/L) and higher GMT (299.1 ± 3.6 IU/L) compared to those with undetectable 60% and 106.2 ± 12.9 IU/L respectively (P<0.05). No significant difference was detected as regards gender or residence, P>0.05. All children with history of rheumatic fever (7 children) or diabetes mellitus (1 child) developed immune response after 2(nd) vaccination series.

CONCLUSION

A booster dose of HB vaccine may be unable to induce sufficient immunological response in children who had undetectable anti-HBs titers. Revaccination for non-responders is an important procedure to increase HBV protection rate.

The toilet tripod: understanding successful sanitation in rural India

Building toilets and getting people to use them is critical for public health. We deployed a political ecology approach specifically to identify the multi-scalar political, economic, and environmental factors influencing toilet adoption in rural India. The research used ethnographic and technical methods in rural villages of West Bengal and Himachal Pradesh over the period September 2012 to May 2013. The elements of successful sanitation adoption depended on three factors (i.e., toilet tripod): (1) multi-scalar political will on the part of both government and NGOs over the long term; (2) proximate social pressure, i.e., person-to-person contact between rural inhabitants and toilets; (3) political ecology, i.e., assured access to water, compatible soil type, and changing land use. This research contributes to studies of sustainable development and global public health by developing a theory and framework for successful sanitation.

Knowledge and perceptions of hepatitis C infection and pesticides use in two rural villages in Egypt

Background

Hepatocellular carcinoma (HCC), one of the most fatal types of malignancy, is increasing worldwide, and particularly in Egypt where there is a confluence of its contributing factors, including high prevalence of hepatitis C virus (HCV) infection, widespread use of pesticides, and diets that are contaminated by aflatoxin B1 (AFB1) in rural areas. We investigated knowledge, attitudes, and prevention practices related to HCV infection and pesticides use in rural Egypt, where over half of the population resides and agriculture is the predominant occupation.

Methods

From two rural villages we recruited 67 residents aged 18–80 years, who completed a 40-item survey that included questions about demographics, knowledge of and protective measures relevant to pesticides use in the home and in agriculture, awareness and perceptions of HCV infection and its treatment and prevention.

Results

Among the 67 study participants, gender distribution was equal, the mean age was 47.2, and one third never attended school. More than 50% reported using pesticides at home, but fewer reported having some knowledge about its health effects. Twelve participants were agricultural workers, and 11 of them applied pesticides in the field and knew about their toxicity; however only one person was correctly using the appropriate protective equipment. Among all the participants, 52 did not know what causes HCV infection, and 42 of those who knew it was a virus mentioned incorrect modes of transmission; and 30 did not know the disease manifestations.

Conclusion

In rural Egypt, there is a significant lack of knowledge of HCV infection and its transmission mode and limited use of protective measures against pesticides despite familiarity with these chemicals.

Impact of regular soap provision to primary schools on hand washing and E. coli hand contamination among pupils in Nyanza Province, Kenya: a cluster-randomized trial

We assessed whether supplying soap to primary schools on a regular basis increased pupil hand washing and decreased Escherichia coli hand contamination. Multiple rounds of structured observations of hand washing events after latrine use were conducted in 60 Kenyan schools, and hand rinse samples were collected one time in a subset of schools. The proportion of pupils observed practicing hand washing with soap (HWWS) events was significantly higher in schools that received a soap provision intervention (32%) and schools that received soap and latrine cleaning materials (38%) compared with controls (3%). Girls and boys had similar hand washing rates. There were non-significant reductions in E. coli contamination among intervention school pupils compared with controls. Removing the barrier of soap procurement can significantly increase availability of soap and hand washing among pupils; however, we discuss limitations in the enabling policy and institutional environment that may have prevented reaching desired levels of HWWS.

Neuropathic pain: is quantitative sensory testing helpful?

Neuropathic pain arises as a consequence of a lesion or disease affecting the somatosensory system and is characterised by a combination of positive and negative sensory symptoms. Quantitative sensory testing (QST) examines the sensory perception after application of different mechanical and thermal stimuli of controlled intensity and the function of both large (A-beta) and small (A-delta and C) nerve fibres, including the corresponding central pathways. QST can be used to determine detection, pain thresholds and stimulus-response curves and can thus detect both negative and positive sensory signs, the second ones not being assessed by other methods. Similarly to all other psychophysical tests QST requires standardised examination, instructions and data evaluation to receive valid and reliable results. Since normative data are available, QST can contribute also to the individual diagnosis of neuropathy, especially in the case of isolated small-fibre neuropathy, in contrast to the conventional electrophysiology which assesses only large myelinated fibres. For example, detection of early stages of subclinical neuropathy in symptomatic or asymptomatic patients with diabetes mellitus can be helpful to optimise treatment and identify diabetic foot at risk of ulceration. QST assessed the individual's sensory profile and thus can be valuable to evaluate the underlying pain mechanisms which occur in different frequencies even in the same neuropathic pain syndromes. Furthermore, assessing the exact sensory phenotype by QST might be useful in the future to identify responders to certain treatments in accordance to the underlying pain mechanisms.

Systematic review: handwashing behaviour in low- to middle-income countries: outcome measures and behaviour maintenance

OBJECTIVES

To describe global approaches to handwashing research in low- and middle-income communities, schools and health care settings using behavioural outcome measurement and temporal study design.

METHODS

Peer-reviewed and grey literature was screened for handwashing studies that evaluated behaviour change. Relevant articles were assessed by their research approach, including the investigator's selected outcome measure and time frame of various study components (e.g., formative research, intervention and evaluation).

RESULTS

The initial search yielded 527 relevant articles. After application of exclusion criteria, we identified 27 unique studies (30 total articles). Of the 27 articles, most were focused in the community setting. Fifteen (56%) documented observed handwashing behaviour, while 18 (67%) used proxy measures (e.g., soap presence, diarrhoea) and 14 (52%) used self-reported behaviour. Several studies used multiple outcome measures. While all studies had an evaluation of behaviour change, there was a dearth of studies that evaluated long-term maintenance of behaviour change after the intervention's conclusion.

CONCLUSIONS

While the literature is replete with a variety of handwashing studies in community, school and health care settings, none have been able to definitively document long-term behaviour change, thereby challenging the sustainability of various interventions. Additionally, there is a need to better understand which research approach is most effective in promoting long-term behaviour compliance in global low- and middle-income settings.

Quantitative sensory testing: a diagnostic tool for painful neuropathy

Quantitative sensory testing (QST) analyzes sensory perceptions of external stimuli of controlled intensity. Both large and small fiber function can be evaluated by applying thermal and mechanical stimuli, thus closing the diagnostic gap for the conventional electrophysiology in the examination of thin and unmyelinated nerve fibers. Detection, pain thresholds and stimulus–response curves can be determined; therefore, QST is a valuable diagnostic tool for identifying both sensory loss (i.e., hypoesthesia and hypoalgesia) and gain (i.e., hyperalgesia and allodynia) in patients with painful or painless neuropathy. Every psychophysical approach QST requires standardized stimuli administration, instructions and data evaluation to achieve valid results. QST can be used to evaluate distinct somatosensory profiles and thus give hints to the underlying mechanisms that occur with different frequencies in different pain syndromes. This might be helpful for the future establishment of mechanism-based pharmacotherapy. Since normative data are available, QST also contributes to the individual diagnosis of neuropathy. The present article gives an outline of QST application in diagnosis and its limitations for the evaluation of neuropathic pain.

Hygiene and sanitation among ethnic minorities in Northern Vietnam: does government promotion match community priorities?

Improving sanitation and hygiene to prevent infectious diseases is of high priority in developing countries. This study attempts to gain in-depth understanding of hygiene and sanitation perceptions and practices among four Ethnic Minority Groups (EMGs) in a rural area of northern Vietnam. It is based on extensive participatory observations in 4 villages and 20 case households over a period of six months (May-October 2008). In addition, 10 key informants and 60 household-members were interviewed and 4 focus group discussions conducted. The study found that among the four selected EMGs the cultural perceptions of hygiene and sanitation which inform everyday hygiene practices did not differ substantially and were similar to hygiene explanations found in the rural majority population elsewhere in Vietnam. However, the difficult living conditions, particularly in highland communities, reinforce a sense of marginalization among the EMGs, which had great impact on how they perceive and respond to government sanitation interventions. The enclosed latrines promoted by authorities are met with reluctance by the EMGs due to cultural perceptions of the body as permeable and therefore, vulnerable to 'dirty air' such as bad smells from human faeces. In addition, the prioritization of specific sanitation hardware solutions by the central government aimed at increasing coverage creates expectations and dependency among the EMGs that hygiene 'comes from the outside society', resulting in low levels of community initiated actions. Based on these findings, we suggest that future hygiene promotion strategies aim for a closer match between community priorities and government hygiene policies, e.g. by allowing for a larger diversity of low-cost sanitation solutions. Scaling up participatory community-based hygiene promotion is also recommended to curb dependency and spark initiatives in ethnic minority communities. Finally, interventions should focus on hygiene "software"--promoting hygiene behaviour changes known to effectively prevent hygiene related diseases.

Capacity building of local governmental and non-governmental organizations on environmental hygiene through a community-based training workshop program

This study was performed to evaluate the feasibility of a joint community-based environmental hygiene program in partnership between local governmental and non-governmental organizations with participants from different professional backgrounds, including inspectors of environmental sanitation and community leaders in Lagos, Nigeria, because no suitable collaboration had been implemented in this area. Qualitative and quantitative evaluations were performed with regard to malaria prevention and community-based environmental hygiene training workshops in three local communities in Lagos, Nigeria. Qualitative evaluation revealed the importance of establishment of close partnerships between local governmental and non-governmental organizations, and possible community participation in the program for its success. A total of 36 participants completed pre- and follow-up assessment before and after the three-day training course. The mean pre-test score was 27.8 +/- 13.9 (mean +/- standard deviation), while that of the follow-up test was 57.1 +/- 17.8. This mean gain of 29.3 +/- 17.4 in the score represented a significant improvement (p < 0.001). The objective of the training workshop, i.e., to implement the community-based environmental hygiene program, was successfully achieved. The training workshop also established good relations between governmental and non-governmental organizations with different professional backgrounds, and demonstrated the potential for sustained collaboration.

Effectiveness of a capacity-building program for community leaders in a healthy living environment: a randomized community-based intervention in rural Vietnam

This randomized controlled study was performed to evaluate the effectiveness of an educational program entitled 'Capacity building for community leaders in a healthy living environment,' and to assess the usefulness of a participatory style of education and the applicability of an intersectoral approach in the educational process. An intervention group and a control group (consisting of 150 and 154 community leaders, respectively) were both evaluated, after the intervention group took part in a 5-day participatory-style educational program. Healthy living environment promotion competency (HPC) was evaluated by an instrument consisted of four competency areas: identifying the steps required for a healthy living environment; understanding the principles to reduce potential health risks; providing public health management to improve the living environment; and applying the principles of health communication skills. Scores between the intervention and control groups were examined to identify changes between the baseline and post-intervention periods. A qualitative evaluation of the educational program by participants and facilitators was conducted to assess the appropriateness of the intervention. The results indicated significant increases in the total HPC score and scores of individual HPC competency areas in the intervention group. Thus, the effectiveness of a capacity building program for community leaders in a healthy living environment was demonstrated. Qualitative evaluation revealed that the participatory-style and intersectoral collaboration approach facilitated the educational process. Community leaders, who are representatives of various sectors and mass organizations within the community, can be important implementers in the promotion of a healthy living environment.

Monitoring progress of the role of integration of environmental health education with water and sanitation services in changing community behaviours

The health benefits of clean water, improved sanitation and better hygiene are now more recognized than ever before. The objective of the present study focused on monitoring the progress of behavioural changes towards appropriate behaviours related to water, environment and sanitation (WES). This was achieved through assessing the baseline community behaviours towards WES, exploring to what extent community hygienic behaviours had changed towards desirable and sustainable behaviours, through monitoring progress. The expected behavioural changes are results of an integrated package; safe water supply, sanitation, and hygiene education interventions produced by governmental and non-governmental organizations. The monitoring progress consisted of three household surveys that were administered over three years in four Egyptian districts within three Governorates; Fayoum, Beni Suef, and El-Menia. Behavioural changes were detected through special observation checklist indicators. These indicators were 7, 6, and 9 indicators each for personal hygienic behaviours, proper handling of drinking water, and proper use and maintenance of simple constructed sanitary latrines. The results from the baseline to mid-term and final surveys suggested improvement in the majority of the household behaviours towards the desirable behaviours. The proportions of the householders who practiced desirable behaviours were not to the same levels in the four districts. The results provide support to the concept that integrated interventions can produce a significant sustainable improvement in health promotion.

Influence of age, temperature, sex, height and diazepam on vibration perception

Vibration perception was quantitatively examined in 92 healthy volunteers (46 females, 36 males, aged 10-71 years). Vibration perception thresholds, vibration disappearance thresholds and vibration thresholds were assessed at the second metacarpal bone, styloid process of ulna, lateral epicondyle of humerus, first phalanx of the big toe, first metatarsal bone, medial malleolus and proximal part of the tibia bilaterally. Vibration sensitivity was found to be age-dependent. Under the age of 60, the correlation was linear. Vibration thresholds depended on body site but they were not related to sex or body side. Temperature and diazepam affect the perception of vibration considerably. Small interindividual variability was found in measurements repeated in 3 consecutive days, after 4 weeks and after a year.

Measurement of light touch perception threshold by contingent negative variation

An objective method developed to measure the threshold of light touch perception using contingent negative variation (CNV) is described. The light touch stimulus was a slight indentation of the skin produced through a displacement controlled stimulating probe (tip diameter of 2 mm). It was applied as the conditioning (S1) stimulus of the classical CNV paradigm of S1, S2, and R. To increase the CNV amplitude, the S2 stimulus was either a red or a yellow LED. The subjects were required to respond to only one of two by pressing a button. When the light touch stimulus was perceived, the CNV was recorded in all 19 healthy adult volunteers. In 14 of them, a systematic determination of the threshold of the ball of the thumb and index finger, thenar, hypothenar, face, shoulder, anterior thigh, foot dorsum and great toe ball, have been done. The thresholds of the light touch perception as defined by objective CNV measurement are very close to the results of the subjective psychophysiological determinations in normals. The amplitude of the averaged CNV (12 responses) started to decrease when stimulus intensity was reduced to the point that the subjects were able to perceive only a fraction of the presented touch stimuli. We believe, therefore, that the objective CNV determination of the light touch perception threshold is precise and sensitive enough to be used in research as well as in clinical applications.

Multiunit neural responses to strong finger pulp vibration. II. Comparison with tactile sensory thresholds

In a companion microneurographic study (Schmidt et al. 1990) maximal multiunit sensory responses to finger pulp vibration were compared with maximal responses evoked by electrical stimulation of the digital nerve. It was found that the MR/ER ratio, i.e. the ratio between the magnitudes of the responses to mechanical and electrical stimulation, decreased with increasing age. The shape of this age-related decline in the ratio corresponded well with the decrease in the number of Meissner corpuscles found in histological studies. In the present study the tactile sensory detection thresholds were measured in the same subjects that participated in the companion study and the relationship between these thresholds and the MR/ER ratios was examined. The tactile sensory detection threshold increased with age. A weak negative correlation was found between the threshold and the ratio. However, after compensation for common age-mediated effects, this negative correlation disappeared. Thus, the results indicate that measurement of tactile sensory detection thresholds and determination of MR/ER ratios may complement each other, giving an indication of different types of derangement of the mechanoreceptive system.

Vibration perception and thermoperception as quantitative measurements in the monitoring of cisplatin induced neurotoxicity

In 20 ovarian cancer patients treated by cisplatin-based chemotherapy quantitative investigations of the vibration and the thermoperception were performed. Following the administration of cisplatin of 300 mg/m2 and more the vibration perception threshold (VPT) was shown to be significantly elevated in all patients, despite the absence of clinical symptoms and signs in a number of patients. The VPT returned within 8 months to its original level in the 2 patients who were followed after cessation of therapy (cumulative dose of cisplatin 450-525 mg/m2). The changes seen in hands and in feet were comparable. There was no significant difference between the left and the right hand side. Thermoperception thresholds did not change during the treatment period. This study shows that quantitative measurement of vibration perception thresholds in patients treated with cisplatin is a relatively simple, accurate and reliable technique. Measurement is only required at the hand. It is concluded that this technique is a valuable tool in the assessment of cisplatin neurotoxicity and may be used in the monitoring of drugs that claim to be of benefit in the prevention and treatment of this affliction.

Diagnostic value of quantitative sensory testing (QST) in carpal tunnel syndrome

The initial sensory symptoms of carpal tunnel syndrome (CTS) are usually intermittent and the clinical neurological examination is often normal. The aim of the present study was to determine the rate of impairment of different somatosensory modalities in CTS by means of the following tests: vibrametry, tactile pulses, von Frey hairs, two-point discrimination (2-PD), graphesthesia and warm and cold perception thresholds. The material consisted of 33 hands with CTS from 22 patients. Each of the first 3 tests was abnormal with elevated thresholds in 17 CTS hands (52%), 2-PD was abnormal in 10 hands (30%), graphesthesia in 8 hands (24%), and warm and cold thresholds in only 5 hands (15%). There was an overlap so that at least one test was abnormal in 27 of the 33 CTS hands (82%). Thus, impairment of sensibility can be demonstrated in a majority of patients with CTS if more than one test is applied. Vibrametry and von Frey hairs are recommended instead of the commonly used 2-PD, since abnormality was more often revealed and since they are equally easy to apply. No individual test was sensitive enough to qualify as a diagnostic criterion when it was applied with the hand in resting position. A significant increase in both sensitivity and specificity can be expected for any test if it is combined with provocation, such as wrist flexion, as has been demonstrated for vibrametry.

Internal neurolysis or ligament division only in carpal tunnel syndrome. II. A 3 year follow-up with an evaluation of various neurophysiological parameters for diagnosis

48 patients with clinical and neurophysiological signs of carpal tunnel syndrome were randomized to any of two operative methods: Internal neurolysis of the median nerve with a microsurgical technique, or simple division of the carpal ligament (flexor retinaculum). After a minimum follow-up period of 3 years 81% of the patients did not report any complaints at all, and all patients considered themselves improved after operation. There was no difference between the operation groups. Therefore there seems to be no justification to perform the more difficult procedure of internal microsurgical neurolysis for treatment of the carpal tunnel syndrome. A study of the neurophysiological parameters before and after restitution showed the highest sensitivity (91%) for the sensory conduction velocity, and the highest specificity for motor distal latency and sensory distal latency (83 and 75% resp.).

Tactile detection threshold determined with single sinusoidal mechanical pulses in the monkey skin

Tactile detection thresholds for single sinusoidal mechanical pulses increased with decreases in the frequency of the stimulus pulse (from 150 to 20 Hz) in a monkey's skin. The results correspond with those of similar electrophysiological studies.

Increase of vibration threshold during wrist flexion in patients with carpal tunnel syndrome

The most prominent symptoms of carpal tunnel syndrome (CTS) are sensory, with intermittent numbness, paraesthesiae and pain in the fingers innervated by the median nerve. No consistent signs are found by neurological examination, however. Conventional sensibility tests are positive in only about 50% of the cases. This applies also to quantitative tests such as measurement of the perception threshold for vibration (VT). In an attempt to find a more reliable indication and improve the diagnostic value of sensory testing, determination of VT was combined with provocation by means of wrist flexion. In a patient group with neurophysiologically verified CTS, all patients exhibited an increase to at least twice the VT value in the fingers innervated by the median nerve. No increase was seen in the little finger or in a control group of patients with digital paraesthesiae but with normal neurophysiological findings. It is concluded that VT measurements during wrist flexion can be used as a supplementary or alternative diagnostic criterion to indicate that the nerve dysfunction is located in the carpal tunnel.

The influence of rate of skin indentation on threshold and suprathreshold tactile sensations

The effects of skin indentation depth and rate on threshold and suprathreshold tactile sensations were investigated. Indentation rates between 0.3 and 10 mm/sec had little effect on the absolute tactile thresholds measured in terms of indentation depth. Slower rates resulted in increased absolute thresholds. Estimates of the growth in intensity of tactile sensations were made as functions of indentation depth and rate. The fastest rate used (10 mm/sec), for a given depth of indentation, produced the most intense sensation; the slowest (0.1 mm/sec), the least intense sensation. The tactile sensation magnitude estimates, with rate as the parameter, could be described by power functions. At the slowest indentation rate the exponent of the function was 1.36. At faster indentation rates (0.4, 1.0, and 10 mm/sec), two functions of markedly different slopes were required to describe the estimates. The exponents of the power functions were between 0.38 and 0.49 for indentation depths up to about 0.9 mm, and between 1.07 and 1.43 for deeper indentation depths.

Acute pandysautonomia and severe sensory deficit with poor recovery. A clinical, neurophysiological and pathological case study

A patient with acute loss of autonomic functions and virtually all afferent functions of peripheral nerves is described. The course was chronic and the outcome fatal. The clinical course was followed with measurements of sensory thresholds and conduction velocities, autonomic tests and microneurographic recordings. Neuropathological changes were severe and localised in the peripheral nervous system. Previously reported similar cases were reviewed. It was concluded that acute pandysautonomia is a disorder similar to the Guillain-Barré syndrome; the course is often protracted and residual neurological deficit common.

Influence of the rate of force application on the absolute psychophysical threshold level of periodontal mechanoreceptors in man

In seven volunteers, controlled small forces were applied in an axial direction to a maxillary central incisor. The forces were generated by a stimulating device supported by the maxillary molars. The stimuli had a symmetrical triangular shape; force-application rates were varied from 1.88 to 960 mN/s. Threshold levels of sensation were determined at the various force-application rates. The relation between force-application rate and threshold level was negative, using 1.88, 3.75 and 7.5 mN/s stimuli. This trend was interrupted as threshold levels were higher at 15 than at 7.5 mN/s. In the range of more rapidly applied forces, 15-960 mN/s, the relationship was also negative, consistently, with a slope of -0.22 of the linear regression line after logarithmic transformation. It was concluded that the periodontal mechanoreceptive unit, as far as conscious functioning is concerned, may be described as a relatively inaccurate static force-detector when small magnitude forces are applied at low rates. Some rate sensitivity appears with more rapidly-applied stimuli.

Summation of rapid tactile stimuli in parietal lobe disease

The perception threshold for trains of rapid tactile pulses, applied to the index finger, has been measured in patients with parietal lobe lesions and in patients with median nerve lesions. The former patients had increased perception thresholds for single tactile pulses on the abnormal side. With successively prolonged pulse trains, the threshold decreased exponentially to reach a stable level after 150-400 ms. In contrast, the median nerve patients had increased perception thresholds for tactile pulses irrespective of pulse train duration.

Effects of aldose reductase inhibitor treatment in diabetic polyneuropathy - a clinical and neurophysiological study

The efficacy of treatment with an aldose reductase inhibitor (1,3-dioxo-1 H-benz-de-isoquinoline-2(3H)-acetic acid, AY-22,284, Alrestatin) on peripheral nerve function in diabetic polyneuropathy was assessed. Thirty patients with long-standing diabetes and slight to moderate neuropathy participated in the double-blind placebo trial. Clinical examination, sensory threshold determinations for vibratory, tactile and thermal stimuli, conduction velocity measurements and studies of automatic function were performed to evaluate the treatment. Significant differences favouring Alrestatin over placebo were found for many of the measured variables, whereas no changes occurred on placebo. The apparent improvement of neuropathy occurred despite persisting hyperglycaemia. The results indicate that aldose reductase inhibitor treatment may be of value in diabetic polyneuropathy, and provide support for the sorbitol pathway hypothesis of diabetic polyneuropathy.

Peripheral neural basis of tactile sensations in man: I. Effect of frequency and probe area on sensations elicited by single mechanical pulses on hairy and glabrous skin of the hand

Tactile thresholds and sensation magnitudes for single mechanical pulses of varying frequency and probe area were studied in order to provide psychophysical data for correlations of tactile sensations with functional properties of different types of human peripheral nerve fibers. Single mechanical pulses were delivered to the hairy or glabrous skin of the hand by means of a perspex probe (area 0.07, 0.7, 3.1, or 12.5 sq.-mm) fixed to the moving coil of an electromechanical vibrator. The frequency of the single pulse was 20, 60 or 150 HZ. Absolute and touch thresholds were measured with a method of production. Suprathreshold sensations were measured with the method of magnitude estimation (6 predetermined displacement amplitudes ranging from 50 to 950 micrometers). Both absolute and touch thresholds were significantly higher on the hairy than on the glabrous skin. The absolute thresholds varied between 44 and 140 micrometers on the hairy and between 9 and 45 micrometers on the glabrous skin; the touch threshold varied between 75 and 300 micrometers and 24 and 153 micrometers, respectively. Lower threshold values were obtained on both skin areas with increasing frequency of the pulse and probe area, the latter effect being significant only for the hairy skin. Standardized magnitude estimation functions could be described with power functions on both skin areas, the exponents of the functions varying between 0.70 and 1.41 on the hairy and between 0.55 and 0.86 on the glabrous skin. The equi-sensation contours showed the difference of sensitivity between the skin areas. Larger sensation magnitudes were obtained with increasing frequency of the pulse and probe area on both skin areas. These psychophysical findings indicate that there is a functional difference at absolute sensation thresholds between hairy and glabrous skin. This difference, however, disappears at higher sensation levels.

Variability of sensory threshold determination in clinical use

The variability of perception threshold determination for vibration, tactile stimuli and thermal stimuli, with instruments intended for clinical use, was studied in 13 healthy subjects and 27 patients with chronic polyneuropathy. Normal thresholds for tactile and thermal stimuli were determined in 51 healthy subjects. Determinations were made for vibration on hand, lower leg and foot, for touch on pulp of forefinger and great toe and for temperature on hand and foot. Normal thresholds for both tactile and thermal stimuli were age-dependent. Short-term variation, with intervals of some minutes between determinations, remained within 8-18% change from first value. Long-term variation, with intervals of days to some weeks, was pronounced for all types of threshold, with extremes of -90% and +256% change from first determination in 3 or 4 subsequent determinations. Variation was most marked for tactile stimuli and smallest for vibration, but magnitude and pattern of variation was similar for all sensory modalities and for both patients and healthy subjects. Confidence intervals, derived from analysis of variance, showed than as an average a change of less than -60% or greater than +150% from the initial value was needed to ascertain with 95% probability that a subsequent value will reflect a true change of sensory threshold. Basing every threshold value on 2 or more measurements per occasion will reduce the confidence interval. The main cause of variability seems to be central processing mechanisms, i.e. the psychological variability. With proper attention to the variability, sensory threshold determinations should still be a valuable aid in clinical practice and clinical research.

The relationship between tactile thresholds and histology in the human finger

Touch detection and two-point discrimination thresholds at three sites on the distal phalanx of the little finger were compared with the histology of the same three sites in amputated fingers. No consistent relationship could be demonstrated between sensitivity to touch and the population density of Meissner corpuscles or other organised endings. However, the findings do not negate the suggestion that Meissner corpuscles may be involved in two-point discrimination.

Detection of tactile stimuli. Thresholds of afferent units related to psychophysical thresholds in the human hand

1. Psychophysical thresholds were determined at 162 points in the glabrous skin area of the human hand when slowly rising, triangular indentations of controlled amplitudes were delivered with a small probe. The method of constant stimuli was used with either the two alternative forced choice or the yes-no procedure. It was found that the distribution of the psychophysical thresholds varied with the skin region. Thresholds from the volar aspect of the fingers and the peripheral parts of the palm were low and their distribution was unimodal with a median of 11.2 micrometers. In contrast, there was an over-representation of high thresholds when observations from the centre of the palm, the lateral aspects of the fingers and the regions of the creases were pooled, and the distribution was slightly bimodal with a median of 36.0 micrometers. 2. Nerve impulses were recorded from single fibres in the median nerve of human subjects with percutaneously inserted tungsten needle electrodes. The thresholds of 128 mechanosensitive afferent units in the glabrous skin area of the hand were determined when stimuli were delivered to partly the same points as stimulated for the assessment of the psychophysical thresholds. Of the four types of units present in this area the Pacinian corpuscle (PC) and rapidly adapting (RA) units had the lowest thresholds with medians of 9.2 and 13.8 micrometers, followed by the slowly adapting type I and slowly adapting type II units with medians of 56.5 and 33.1 micrometers. There was no indication of a difference between thresholds of units located in different skin areas. 3. In the region of low psychophysical thresholds there was good agreement between the thresholds of the rapidly adapting and Pacinian corpuscle units and the psychophysical thresholds, particularly at the lower ends of the samples. In the skin regions of high thresholds, on the other hand, practically all psychophysical thresholds were higher than the thresholds of the most sensitive afferent units. Moreover, simultaneous recording of nerve impulses during a detection task indicated that subjects did not detect stimuli strong enough to elicit several impulses in afferent units in this region. 4. Circumstantial evidence led to the conclusion that detection was dependent on one impulse in one or a few rapidly adapting units under optimal conditons in the region of low psychophysical thresholds, whereas it seemed unlikely that activity in Pacinian corpuscle units was crucial. 5. The findings are consistent with the interpretation that human subjects are able to detect an input consisting of a single impulse in a single rapidly adapting unit.

Sensory functions in chronic neuralgia

Eleven patients with sustained neuralgia, in most cases after traumatic nerve lesion, were subjected to quantitative sensory testing with thermal and non-noxious mechanical stimuli. Measurements were made in the pain area and at a homologous site on the contralateral normal side. All patients were hypoaesthetic with raised thresholds for warm and cold or touch, or both. Thermal pain thresholds were also raised in some patients but lowered in others indicating hypersensitivity of the nociceptor system or dysaesthesia for thermal input. In six patients single mechanical stimuli produced a painful response above the touch detection threshold. Reaction time measurements indicated that this painful response to suprathreshold mechanical pulses was measured by magnitude estimation as a function of stimulus amplitude. The results were fitted by power functions, as in normal skin, but with steeper slopes on the abnormal side. Suprathreshold hyperaesthesia (recruitment) may exist in the presence of normal threshold functioning.

A study of reception with the use of focused ultrasound. II. Effects on the animal receptor structures

The possibility of stimulation of receptor structures with focused ultrasound (focused beam of high frequency mechanical waves) was investigated. Stimulation of single Pacinian corpuscle isolated from cat's mesentery resulted in receptor and action potentials. Stimulation of frog's ear labyrinth resulted in evoked potentials recorded from midbrain auditory area, their characteristics being much the same as those for responses to adequate sound stimuli. It is concluded that focused ultrasound is an advantageous agent for stimulation of various mechanoreceptors both isolated and, especially, located deep in the body. Some problems related to sensory specificity are discussed.